The present invention pertains to an improved drill bit for forming boreholes as in drilling oil and gas wells. More particularly, the present invention pertains to drill bits which employ and contain polycrystalline diamond cutting elements, and are usually referred to as "PDC" drill bits.
A problem often found in prior art "PDC" drill bits is erosion which is caused by high velocity drilling fluid acting on the cutting mountings of the cutting elements, on the drill bit face, and on other components of the bit. This shortens the operating life of the drill bit.
Another problem associated with prior art "PDC" drill bits is balling, plugging, or packing of cut material onto the face of the drill bit due to uneven or unbalanced fluid flow over the face of the drill bit which results in reduced penetration rates and inadequate and uneven cooling of the cutting elements and thereby unpredictably diminish the resultant drilling operation.
Because of the above problems, "PDC" drill bits have heretofore been used economically only in drilling a very limited range of different rock and earth formations.
No known prior art drill bit has both a means for controlling fluid erosion and simultaneously a means for preventing balling or plugging of a bit face. The present invention provides a drill bit which controls fluid erosion and prevents plugging of the bit face while making hole.